(Greek):
1.pertaining to the underworld 2.dwelling underground 3.rising up (out of the ground)(B.M.)

Orpheus, a musician who went to Hades (the subterranean land of the dead in Greek myth) to ask for his lover's return to the world of the living, played music for his chthonic audience so beautifully that they relented to his request and let him try to take her back up to the surface.